Propane gas level monitor

Hi all,

Newbie here. I was wondering if anyone might be able to help or give any suggestions. I would like to build a device that can be used to monitor gas (propane) level in a cylinder.
This device is needed for household usage and would like to use it to monitor gas level remotely.
Where can one start building such device. Apologies if this is not the right forum.

Otherwise, if anyone knows a freelancer that might be able to help build a prototype, that would be highly welcome.

Thanks in advance

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Welcome to the community @asqrd

The easy/safest way that I know of would be to measure the weight of the propane cylinder with a Load Cell and a Particle Device.
The tanks have a Tare Weight stamped in them. The BTU value of Propane is fairly constant, so you can quickly know how much cook time is remaining (when you know the BTU rating of the appliance).

A direct method would be to measure the gas pressure with a suitable transducer prior to the regulator, but I'd recommend temperature compensation when dealing with Propane. This probably wouldn't be the best route to start out with, and it won't be more accurate than measuring the weight.

Sounds like a fun project… you might be able to get some motivation from similar products out there on best way to sense it. For example:

Mopeka Pro Check Sensor - Wireless Propane Tank Magnetic Sensor Level Indicator - Propane Gas Tank Pressure Gauge Electronic for BBQ Grill - Remote Ready Propane, Butane And Fuel Level Gauge With App

I’m sure pressure or weight as @Rftop mentioned would work as well! Personally I think its more fun building your own Particle.IO powered monitor. Maybe some sort of ultrasonic sensor can detect it as looks like that’s what’s used in that product.

Ultrasonic is a neat idea for this @jgskarda :grinning:

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I can’t take the credit… I believe @mohit shared a link to mopeka during a call or maybe someplace else…. I forget where it was. Seemed cleaver way to detect it. If you figure out the sensing part, maybe there is a need for a cellular version.

I’m tempted to buy one from Amazon to play with it but I’m one of those guys that would swap out cylinders when it’s empty and leave it on the cylinder when I exchange it for a full one. Sticks on like a magnet so I’m sure easy to forget. :rofl:

I thought about this some more last night:
Weight would definitely be easier than estimating the liquid level through different sizes of steel tanks via ultrasonic through the tank's wall thickness.
Weight would be a direct measurement with no estimation.
Every Particle device can sample a load cell.
Plus, your comment about forgetting the magnet (ultrasonic) device on the tank during trade-in is a great point.

In the US, we follow the 80/20 rule - so we only fill a tank to 80% capacity for a Safety Margin for gas expansion. A 20-lb tank would get about 17 pounds of Propane. Each pound produces roughly 21,500 BTUs of energy.

I am surprised with how inexpensive the $50 Ultrasonic product is that you linked to though. I wouldn't think we could get anywhere close to that price with proper weight measurement.